title: Risk behavior among women enrolled in a randomized controlled efficacy trial of an adenoviral vector vaccine to prevent HIV acquisition.
abstract: OBJECTIVE
  Report of risk behavior, HIV incidence, and pregnancy rates among women participating in the STEP study, which is a phase IIB trial of MRKAd5 HIV-1 gag/pol/nef vaccine in HIV-negative individuals who were at high risk of HIV-1.
  
  
  METHODS
  Prospective multicenter, double-blinded, placebo-controlled trial.
  
  
  METHODS
  Women were from North American, and from Caribbean and South America (CSA) sites. Risk behavior was collected at screening and 6-month intervals. Differences in characteristics between groups were tested with chi-square, two-sided Fisher's exact tests, and Wilcoxon rank-sum tests. Generalized estimating equation models were used to assess behavioral change.
  
  
  RESULTS
  Among 1134 enrolled women, the median number of male partners was 18; 73.8% reported unprotected vaginal sex, 15.9% unprotected anal sex and 10.8% evidence of a sexually transmitted infection in the 6 months prior to baseline. With 3344 person-years of follow-up, there were 15 incident HIV infections: incidence rate was 0.45 per 100 person-years [95% confidence interval (CI) 0.25, 0.74]. Crack cocaine use in both regions [relative risk (RR) 2.4 (1.7, 3.3)] and in CSA, unprotected anal sex [RR 6.4 (3.8, 10.7)], and drug use [RR 4.1 (2.1, 8.0)] were baseline risk behaviors associated with HIV acquisition. There was a marked reduction in risk behaviors after study enrollment with some recurrence in unprotected vaginal sex. Of 963 nonsterilized women, 304 (31.6%) became pregnant.
  
  
  CONCLUSIONS
  Crack cocaine use and unprotected anal sex are important risk criteria to identify high-risk women for HIV-efficacy trials. Pregnancy during the trial was a common occurrence and needs to be considered in trial planning for prevention trials in women.
authors.affiliation: Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60162, USA. rmnovak@uic.edu
authors.forename: Richard M
authors.initials: RM
authors.lastname: Novak
authors.forename: Barbara
authors.initials: B
authors.lastname: Metch
authors.forename: Susan
authors.initials: S
authors.lastname: Buchbinder
authors.forename: Robinson
authors.initials: R
authors.lastname: Cabello
authors.forename: Yeycy
authors.initials: Y
authors.lastname: Donastorg
authors.forename: John-Peter
authors.initials: JP
authors.lastname: Figoroa
authors.forename: Hend
authors.initials: H
authors.lastname: Abdul-Jauwad
authors.forename: Hend
authors.initials: H
authors.lastname: Adbul-Jauwad
authors.forename: Patrice
authors.initials: P
authors.lastname: Joseph
authors.forename: Ellen
authors.initials: E
authors.lastname: Koenig
authors.forename: David
authors.initials: D
authors.lastname: Metzger
authors.forename: Magda
authors.initials: M
authors.lastname: Sobieszycz
authors.forename: Mark
authors.initials: M
authors.lastname: Tyndall
authors.forename: Carmen
authors.initials: C
authors.lastname: Zorilla
mesh_terms: D016915:AIDS Vaccines / Q000008:administration & dosage / Q000276:immunology*; D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D000260:Adenoviruses, Human / Q000235:genetics; D000293:Adolescent; D000328:Adult; D017691:Caribbean Region; D004311:Double-Blind Method; D004337:Drug Carriers / Q000008:administration & dosage; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009656:North America; D010919:Placebos / Q000008:administration & dosage; D011247:Pregnancy; D012309:Risk-Taking; D012725:Sexual Behavior; D013020:South America; D019966:Substance-Related Disorders
chemical_list: D016915:AIDS Vaccines; D004337:Drug Carriers; D010919:Placebos